Ionic conductivity is a property where a material is able to conduct electricity through the movement of ions. Oxide ion conductors can be used in solid oxide fuel cells, which can be used to burn fuels more efficiently. High temperature delta-Bi2O3 is the best oxide conductor known with a conductivity of 1 S/cm at 750 °C, but it is only stable from 730 °C to 804 °C. By doping the lanthanides La and Dy, stable structures can be performed with conductivity of 0.01 S/cm at temperatures of 550 °C and 700 °C respectively, outperforming the currently-used yttria stabilised zirconia, which needs a temperature of 800 °C for the same conductivity. The purpose of this experiment is to investigate the structural features on an atomic scale of the materials Bi0.775Ln0.225O1.5 (Ln = La, Dy) to understand why they are good ionic conductors.